During a regular checkup of an 8-year-old child, you note a loud first heart sound with a fixed and widely split second heart sound at the upper left sternal border that does not change with respirations. The patient is otherwise active and healthy. Which of the following heart lesions most likely explains these findings?
a. Atrial septal defect
b. Ventricular septal defect
c. Isolated tricuspid regurgitation
d. Tetralogy of Fallot
e. Mitral valve prolapse
the answer is below…
The United States Medical Licensing Examination, or USMLE for short, is a three-part licensing examination that is required in order to receive a license to practice medicine within the United States.
The USMLE assesses a physician’s ability to apply knowledge, concepts, and principles, and to determine fundamental patient-centered skills that are important in health and disease and that constitute the basis of safe and effective patient care.Examination committees composed of medical educators and clinicians from across the United States and its territories prepare the examination materials each year.
This exam is designed by the Federation of State Medical Boards and the National Board of Medical Examiners to determine whether or not an individual understands and can apply the knowledge necessary to practice medicine safely and intelligently.
The USMLE is actually comprised of three different exams that are referred to as steps, which examine the individual’s knowledge of specific topics related to the field of medicine such as basic science, medical knowledge, medical skills, clinical science, and the application of all of these skills and areas of knowledge in the medical field.
All three steps of the USMLE include a series of computerized multiple-choice questions, but the format of the exam and the information covered in each multiple-choice section is different for each step of the USMLE. The USMLE Step II also has a clinical skills portion that examines an individual’s ability to work with real patients and the USMLE Step III has a computerized patient simulation portion in addition to the multiple-choice section of the exam. In order for an individual to receive a license to practice medicine, the individual must pass all three steps of the USMLE.
The correct answer is a; Atrial septal defect.
Most commonly, children with an atrial septal defect (ASD) are asymptomatic, with the lesion being found during a routine examination. In older children, exercise intolerance can be noted if the lesion is of significant size. On examination, the pulses are normal, a right ventricular systolic lift at the left sternal border is palpable, and a fixed splitting of the second heart sound is audible. For lesser degrees of ASD, surgical treatment is more controversial. Ventricular septal defects commonly present as a harsh or blowing holosystolic murmur best heard along the left lower sternum, often with radiation throughout the precordium. Tricuspid regurgitation is a middiastolic rumble at the lower left sternal border; a history of birth asphyxia or findings of other cardiac lesions often is present. Tetralogy of Fallot is a common form of congenital heart disease. The four abnormalities include right ventricular outflow obstruction, ventricular septal defect, dextroposition of the aorta, and right ventricular hypertrophy. The cyanosis presents in infants and in young children. Mitral valve prolapse occurs with the billowing into the atria of one or both mitral valve leaflets at the end of systole. It is a congenital abnormality that frequently manifests only during adolescence or later. It is more common in girls than in boys and seems to be inherited in an autosomal dominant fashion. On clinical examination, an apical murmur is noted late in systole, which can be preceded by a midsystolic click. The diagnosis is confirmed with an echocardiogram that shows prolapse of the mitral leaflets during mid- to late systole. Antibiotic prophylaxis is recommended for dental work (especially if a murmur is present), as the incidence of endocarditis can be higher in these patients.